Planimeter.



No. 783,568. l PATENTED FEB. 28, 1905. E. F. CHASE.

PLANIMETER. APPLICATION FILBDAB. 5, 1904.

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Witnesses.

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ltlinrlric Patented February 2S, 1905.

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ERNEST F. CHASE, OF HRIDGEPORT, CONNECTICUT.

SPECIFICATION forming part of Letters Patent No. 783,568, dated February28, i905.

Application tiled March 5, 1904. Serial No.l96,651.

Be it known that'l, lCnNas'r F. Cease, a citizen of the United States,residing at Bridgeport, county of Fairfield, State of Connecticut, haveinvented a new and useful Planimeter. ot which the following isaspecitication.

.rl/ly invention has `["or its object to provide an attachmentapplicableto planimeters et the well-known Collin type which will enable theoperator to take instantly and without any con'iputation whatever themean ellective pressure el an indicator-diagram.

l/Vith this and other objects in view l have devised the noveldetachable planirneter-scale, oi which the l" llowing description, inconnection with the accompanying' drawings, is a specilication,reference characters being used to indicate the several parts.

Figure 1 is a plan View et' a planimeter oi' the Collin type with anindicator-diagrain in place thereon illustrating the application theretooi niy novel scale; Fig. 2, a section oi' the scale and the tracer-armenthe line in dicated by 2 in Fig. l; Fig. 3, a perspective oi' thescale-piece detached; Fig. 4t, an end view of the scale detached, andFig. 5 is a perspective illustrating' a variant 'torni of the inventionin which the indicator-pointer is ear ried by the tracer-arm.

iO denotes the planimeter-base; 1l, the usual sottpaper slip; 12, aplate secured to the base and having a groove 13 to receive theguide-pin 14 ot the tracer-arm l5; 1G, a reniovable weight by which theguide-pin is retaine(`l in the groove; 1T, the traeing-point; i8, theverner;v 19, the nieasnring-wheel; 20, an ii'ldicator-diagrarn; 2.1, alxed retainingclanip, and 22 an adjustable retaining-clamp by which theindicator-diagrarn is retained upon the base. These parts are all incornnlon use on planiineters of the Uoliin type.

My present invention consists ol the detachable scale, which l haveindicated as a whole by A and which slides over the adjustableretaining-clamp.

',lhe scale consists, essentially, of a traine or carrier 23 and ascale-piece 2st, rotatably mounted thereon. The traine is shown asprovided with end pieces E25 and the scalel piece as provided in itsends with central conical recesses 2G, which are engaged by the pointsof set-screws 27, which engage the end pieces, thus making thescalepieces interi changeable and providing tor ser les ofc` anycharacter that may be required. '.lhe setscrews are tightened upsuliiciently to hold the scale-piece against rotation under the ordinaryconditions ota use, but at the saine tinie permitting it to be rotatedin setting. I have shown the scale-piece as adapted to receive eightscales, which are indicated by 2b. '.lhese scales are graduated tocorrespond with the strength oi' the various pressure-springs used inindicators. as eight, ten, iit'teen, thirty pounds, &c. The end piecesare shown as provided with slots 29, which receive the adjustable clamp,as clearly indicated in Fig. l, my novel scale being applied to aplaniuieter by siniply sliding' it over the tree end, of the adjustableclamp which is received in the slots. Coacting with the scales upon thescale-piece is a pointer 30. l'n the torni illustrated in Figs. l, 2,and et this pointer is mounted to slide on a rod 31, the ends of whichare rigidly secured in end pieces This 'torni oi pointer is providedwith an arin 32, which is adapted to be engaged by the tracing-pointupon the tracer-arn1, as will be lnore lully explained. ln the it'orinillustrated in Fig. 5 the pointer, whichin this ilorln l have indicatedby 33, is secured to and is carried by the tractrarni.

The operation is as `follows: ln order to de termine thel ineanellcctive pressure o1 steam in a cylinder during a stroke ol the pistonby nleans otI iny novel scale, the )pr-n'ator lirst uses the planinieterin the usual manner. The Zero-niark in the scale upon the measuringwheel is caused to register with the zeroflnarl; in the Vernier when thetracing-point is at the extreme right end ot' the diagram, as in Fig. 1.The diagram is then traced by the tracing-point in the usual manner.Alfter tracing the diagram and when the tracing-point is again at thestarting-point the lneau effective pressure is obtained as follows: .lfthe diagram is made by an indicator having an eightpound spring, thescale-piece is turned to place the corresponding scale thereon in po*sition to register with the pointer, as in Figs. l and 5, the scalebeing of course located on the sliding clamp so that the Zero-line ofthe scales will coincide with the starting position of thetracing-point. In the form illustrated in Figs. l, 2, and 4 the arm ofthe pointer is then placed in engagement with the tracingpoint and thelatter is moved upward along the inner face of the sliding clamp, as inFig. l, until the zero-mark upon the measuringwheel again registers withthe Zero-mark oi' the vernier.

In the form illustrated in Fig. 5, in which the pointer is carried bythe tracer-arm instead of there being an independent pointer on thescale, the operation is precisely the same, as indicated in Fig. 5, inwhich the scale is shown as taking the mean effective pressure of adiagram from an indicator having an eight-pound spring. The full linesupon the scale indicate pounds of pressure. It will be noted, therefore,that the mean effective pressure indicated in Fig. 5 is six and onehalfpounds.

Having thus described my invention, I claimv 1. A scale for taking themean eective pressure of indicator-diagrams comprising a planimeterhaving a tracer-arm, a removable rotatable scale-piece having scalescorresponding with the pressure-springs of indicators, a

pointer carried by said tracer-armand adjacent to but separate from thetracing-point thereof, said pointer overlapping the scalepiece.

2. A scale for taking the mean effective pressure of indicator-diagramscomprising a frame adapted for attachment to a planimeter, a rotatablescale-piece having scales corresponding with the pressure-springs ofindicators and a pointer mounted to slide upon the frame which coactswith the scales upon the scale-piece and is provided with an arm adaptedto be engaged by the tracing-point of a planimeter, the said scale-piecebeing mounted in position to coact with said pointer.

3. A scale for taking the mean effective pressure of indicator-diagrams,comprising a frame having slots to receive the sliding clamp of aplanimeter by which it is carried, a rotatable scale-piece having scalescorresponding with the pressure-springs of indicators and a coactingpointer which is operated by the tracer-arm of a planimeteiy the saidscalepiece being mounted in position to coact with said pointer.

4. The combination with the tracer-arm and adjustable clamp of aplanimeter, or' a frame adapted to engage the adjustable clamp,arotatable scale-piece removably supported by the frame and havingscales corresponding with the pressure-springs or' indicators and acoacting pointer operated by the tracer-arm, said pointer being separatefrom but adjacent to the tracing-point of said arm and overlapping thescale-piece.

5. A planimeter having a scale adjacent to the end of the tracer-arm,and a pointer mova'ble along' and overlapping' said scale and adapted tobe controlled in its movements by the said tracer-arm, said pointerbeing separate from but adjacent to the tracing-point of said arm.

6. A planimeter having a series of scales adjacent to the end of thetracer-arm, and a pointer separate from but adjacent to thetracing-point of said arm and movable along and overlapping' said seriesof scales and adapted to be controlled in its movements by the saidtracer-arm, either one ol' said scales being adapted to be placed inoperative position to coact with said pointer. j

In testimony whereof I afiix my signature in presence of two witnesses.

ERNEST F. CHASE.

I/Vitnesses:

A. M. WoosTnR, S. IV. ATHERTON.

